No Digital Modulation Working

GNU Radio
1

Hi all,
I was trying to make a transceiver working on any digital modulation. I
have tried GMSK, PSK, QPSK, QAM and other blocks available in gnuradio
companion. But non of them works. All of them works in loop back manner
but when ever I try to transmit and receive on air it simply doesn’t
work. In the attached file I am using GMSK while transmitting a video
file. I have also tried audio file, and even a simple sine wave but all
in vain. I am using USRP N210 with SBX daugherboard with VERT 2450
antenna. All of the equipment works as I was succeeded in transmitting
my voice while doing frequency modulation. If anybody can tell me about
any mistake while seeing the attached file or provide me with any
transceiver using any digital modulation which should work on latest
gnuradio with USRP N210 that would really be a great help.
I really appreciate your help.
Regards.
Ahmed.

2

Did you compensate for the LO offset between Tx and Rx ?

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3

Can you give me any clue how to do that?
Regards.

From: sumitstop [email protected]
To: [email protected]
Sent: Monday, October 22, 2012 9:18 PM
Subject: Re: [Discuss-gnuradio] No Digital Modulation Working

Did you compensate for the LO offset between Tx and Rx ?

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4

On 10/22/2012 03:03 PM, Ahmed Z. wrote:

attached file or provide me with any transceiver using any digital
modulation which should work on latest gnuradio with USRP N210 that
would really be a great help. I really appreciate your help.
Regards. Ahmed.

One issue is that all the TX samples are clipping.
You actually want a transmit amplitude < 1.0

-josh

PS this project may also interest you:
https://github.com/buoyboy/pre-cog

5

Have a look on this

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